Probably official apologies were issued or something...
I too never heard of this particular incident, but it's not an unprecedented event in any case. For example, aerial engagement between Soviet Yaks and American P-38s occurred above southern Serbia in 1944 with casualties on both sides. Americans were on a mission to attack German units retreating from Greece, but attacked advancing Soviets by mistake.

The incident sounds completely in character with the theater of operations. The Soviets were at the end of August Storm - a three pronged assault that started on August 9th (as specified at Yalta). David Glantz's book (of the same name) is a must read.
The Soviets intended to get as far and go as fast as they possibly could to grab territory - and their effectiveness took the Americans by surprise in Korea. So onrushing Soviet tanks and troops + para landings and amphibious landings would make for a very 'dynamic' front - into which a relief B-29 could get shot down. Klantz doesn't mention the incident. Eager to learn more.

"Hog Wild" B29-15-BA serial number 42-63436 882nd BS, 500th BG 73rd BW.
Crew were later returned, aircraft was not.
A second B29 also was forced down this date.
"Buckin' Bronc" B29-80-BW serial number 44-70136 same Squadron as above a/c.

While the crew was interned for sixteen days at a former Japanese POW camp in Hungnam, northern Korea, Soviet and American commanders traded angry cables. Eventually, the B-29 crew was rescued by a C-46 rapair plane, and 354 Allied POWs were transported to the American zone of Korea by rail about a week later.